Mastectomy is a surgical procedure designed to remove one or both breasts as part of treatment for breast cancer. The extent of a mastectomy can vary depending on the stage and type of the cancer. A simple or total mastectomy involves removal of the entire breast tissue, while a radical mastectomy, which is less common, requires removal of the whole breast along with the lymph nodes in the armpit and chest muscle underneath the breast. A double mastectomy is the removal of both breasts. The surgeon may perform mastectomy with or without immediate breast reconstruction, depending on the patient's preference and medical condition. It's done under general anesthesia and may require a hospital stay of a few days to a week.

The procedure is performed by making an incision on the breast to expose the tumor and the surrounding tissue. The entire breast tissue is then removed by cutting it away from the skin and the chest muscle. The edges of the tissue removed are examined to ensure all cancer cells have been taken out. If the cancer has spread to the lymph nodes in the armpit, some or all of them may also be removed. After the removal, the wound is closed with stitches. If immediate reconstruction is chosen, it could be performed using implants or tissue from other parts of the body. Post-operation, patients usually require physical therapy to restore arm movement and strength. Long-term follow-up care after mastectomy often includes hormone therapy, radiation therapy, or chemotherapy to kill any remaining cancer cells.